Shin Mi-Ra, Son Jong-Tae
Department of Nano Polymer Science and Engineering, Korea National University of Transportation, Chungju, Chungbuk, 380-702, Korea.
J Nanosci Nanotechnol. 2019 Mar 1;19(3):1330-1334. doi: 10.1166/jnn.2019.16177.
Polypropylene (PP) separators essentially have poor compatibility with normal liquid electrolytes, including EC/DEC, due to the low surface energies of their hydrophobic surfaces. Therefore, they have a poor ability to retain electrolyte solutions within the separators because of low absorption capacity for the liquid electrolytes, which could directly damage the AC impedance and C-rate performance of LIBs. This study aims to improve the hydrophilicity and adhesion properties using (3-aminopropyl)triethoxysilane (APTES) coating on hydrophobic PP separators. Their surfaces were treated with a thin and stable silane layer, using APTES with -NH₂ of the hydrophilic group. Hydrophilic PP separator surfaces with pore structures were fabricated by a facile solution-immersion method. The contact angle of the APTES-PP separator decreased from 102±2.5° to 60±1.5°. The electrochemical measurement results indicate that the cell using the modified PP separator showed a better initial discharge capacity of 165.79 mAh g during the first cycle, at a current density of 0.1 C, as compared with the initial discharge capacity (141.61 mAh g) of the cell with a bare PP separator. The performances of all cells with coated PP separators were improved with regard to interfacial resistance, discharge capacity and C-rate capacity, compared to the uncoated PP separator.
由于聚丙烯（PP）隔膜疏水表面的表面能较低，其与包括碳酸乙烯酯/碳酸二乙酯（EC/DEC）在内的普通液体电解质的兼容性很差。因此，它们在隔膜内保留电解质溶液的能力较差，因为对液体电解质的吸收能力较低，这可能直接损害锂离子电池的交流阻抗和倍率性能。本研究旨在通过在疏水PP隔膜上涂覆（3-氨丙基）三乙氧基硅烷（APTES）来提高其亲水性和粘附性能。使用带有亲水性基团-NH₂的APTES对其表面进行处理，形成一层薄而稳定的硅烷层。通过简便的溶液浸渍法制备了具有孔结构的亲水性PP隔膜表面。APTES-PP隔膜的接触角从102±2.5°降至60±1.5°。电化学测量结果表明，与使用裸PP隔膜的电池的初始放电容量（141.61 mAh g）相比，使用改性PP隔膜的电池在0.1 C的电流密度下，第一个循环的初始放电容量为165.79 mAh g，表现更好。与未涂覆的PP隔膜相比，所有涂覆PP隔膜的电池在界面电阻、放电容量和倍率容量方面的性能均有所提高。
